Conservative columnist Mark Steyn on Thursday outlined the difference between Democratic presidential frontrunners Joe Biden and Bernie Sanders, saying that Biden is being forced to run a "dishonest" race while Sanders has been 'romanticized' by the "new" Democratic Party.

"I don't think it's his skin color or his age," Steyn said of Biden on Fox News' "Tucker Carlson Tonight," "because as much as I enjoy hearing all these people beat up on a 76-year-old white man, his principal rival in the Democratic primary is a 77-year-old white man.

"And the difference between them," Steyn told Tammy Bruce, who was filling in for Tucker Carlson, "I think is that Bernie is a romance for his supporters. He is a romantic figure, a romantic, insane figure, but he is a romantic."

Biden formally announced his candidacy with a video posted Thursday morning.

"The core values of this nation, our standing in the world, our very democracy, everything that has made America -- America -- is at stake. That’s why today I’m announcing my candidacy for president of the United States," Biden added in a Twitter message.

Steyn said Biden has been "disowned" by his own party and seems like he's now trying to be someone other than the politician he has been his entire career.

"Biden is tired and in the awful position of being unable to run as himself, because the Democrats have basically disowned 90 percent of what Joe Biden has been doing in Washington the last 45 years," Steyn said.

"So that's a terrible problem for a guy, when you have to run in an essentially dishonest way, which is why he gave this a tortured and weird rationale as to why he has decided to get into the race in this video.

"Bernie has it way easier," Steyn added. "Bernie just gets to be Bernie, and Biden is trying to be something other than Biden."